Push button stations



April 1961 R. P. BALLOU 2,979,581

J PUSH BUTTON STATIONS Original FiledAug. 5, 1948 3 s t .s t 2 I l I 42ans 3615 a8 3 40 42 IN VEN TOR. fi/ch aro F? Bod/0a A ril 11, 1961 R. P.BALLOU PUSH BUTTON STATIONS 3 Sheets-Sheet 3 Original Filed Aug. 5, 1948INVENTOR. R/charc/F? Bal/ou ATTORNEY PUSHBUTION STATIONS Richard P.'Ballou, Hartford, Conn., assignor to Federal Pacific Electric Company,a corporation of Delaware Original applications Aug. 5, 1948, Ser. No.42,718, now Patent No. 2,680,794, dated June 8, 1954, and July '31,1953, Ser. No. 371,526, now Patent No. 2,843,686, dated July 15, 1958.Divided and this application Feb. 14, 1958, Ser. No. 731,560

Claims. (Cl. 200-42) The present invention relates to push buttonstations which are used in conjunction with electrically operatedapparatus.

A push button station ordinarily comprises, in one enclosure, anassembly of manually operable switches and may include one or more pushbutton switches, for example, a start switch and a stop switch manuallyoperable by push buttons, a rotary selector switch which is usuallyactuated by a manually operable rotary knob, and one or more pilotlights. However, a push button station may be provided only with pushbutton switches or only with rotary switches or only with pilot lights,or with any combination of such elements. Furthermore, these elementsmay be mounted in different positions within the enclosure. Also, one ormore of the push buttons, especially the stop button, may have mushroomheads, and various other devices, such as interlocks, lock-offs, or keylocks may be added. Heretofore, the various elements and modificationsusually required that the enclosure be provided with openings ofditferent sizes. For this reason, it was heretofore necessary for themanufacturer either to manufacture the push button stations on order, inaccordance with the requirements specified in advance with the order, orto keep in stock a very large number, say several hundred, differentcovers in order to satisfy the different requirements of push buttonstations equipped with various elements or with different numbers ofelements.

One object of the present invention is to reduce the number of differentcovers necessary to meet the different requirements of various pushbutton stations. Another object is to provide a station that may bemounted either in a vertical position or in a horizontal position andyet have all markings or functional designations of the elementsdisposed horizontally for normal reading thereof. Another object is theprovision of a mechanical design whereby the same elements can beprovided either in a station of the surface type or in a flush station,with minimum adaptation requirements. A further object is to provide astation which eliminates the requirements for name or designation platesfor the switches or pilot lights.

A further object of the present invention is the provision of animproved key lock device for one or more switches of a push buttonstation.

Another object of the invention is to provide a push button station inwhich one or more of the push buttons may be provided with heads of themushroom type, the push buttons of said type being of improvedconstruction, particularly in respect to their removable securement tothe companion stems of the push buttons whereby to enable said heads tobe properly secured to said stems and yet be removable therefrom,externally of the cover of the station, when it is desired to removesaid cover for access to the interior of the station enclosure.

Another object is the provision of an interlock for adjacent push buttonswitches of a push button station in order to prevent the simultaneousoperation of both switches, the switch casings of the interlock being ofsuch United States Patent 0 2,979,581 Patented Apr. 11 1961 positionwithout the use of fastening devices or other fittings.

The above and other objects, features and advantages of this inventionwill be fully understood from the following description considered inconnection with the ac companying illustrative drawings.

In the drawings: I Fig. 1 is a perspective view of a push button stationembodying the present invention,'said station being shown in verticalposition, and the functional designations or legends being horizontallydisposed for correct reading; Fig. 2 is an inner plan view of the cover,removed from the frame of the enclosure, showing also the key lock;Figs. 3 and 4 are sectional views on the lines 3-3 and 4-4,respectively, of Fig. 2, one of the push buttons being shown in dottedlines in Fig. 4;

Figs. 5 and 6 are fragmentary sectional views on the lines 5-5 and 6'6,respectively, of Fig. 1; i Fig. 7 is a front view, in elevation, of thepush button station, showing the same in horizontal position, andshowing the functional designationsor legends in horizontal positionsfor the correct reading thereof;

Fig. 8 is a sectional view of a push button switch, on the line 8-8 ofFig. 7;

Fig. 9 is a sectional view on the line 99 of Fig. 8; Fig. 10 is afragmentary sectional view of a selector or rotary switch, on the line10-10 of Fig. 7;

Fig. 11 is a sectional view on the line 11--11 of Fig. 10; Fig. 12 is asectional view on the line 1212 of Fig. 8; Fig. 13 is a sectional viewon the line 1313 of'Fig. 7; Fig. 14 is a front view of the parts shownin Fig. 13, the push button being shown locked in retracted position, apart of the head of the push button being cut away for the purpose ofillustration;

Fig. 15 is a sectional view on the line 1515 of Fig. 7; Figs. 16 and 17are perspective views of releasable holding elements of the push buttonand rotary switches, respectively;

. Fig. 18 is a front view of a push button station of the flush type;

Fig. 19 is a sectional view on the line 1919 of Flg. 18, the switchesbeing shown in-side elevation;

Fig. 20 is a perspective sectional view on the line 2020 of Fig. 19; I

Fig. 21 is a perspective sectional view on the line 21-21 of Fig. 19;and

Fig. 22 is an end view of the operating member of the selector switch,the operating knob being removed.

Referring now to the drawings in detail, there is shown a push buttonstation 10. The enclosure 12 is in the form of a frame having similarend walls 14 and 16 and a rear wall 18 of the same width as said endwalls. As here shown, the cover 20 of the enclosure is U-shaped in crosssection having the front part-22 and the side parts 24. The end walls 14and 16 of the frame 12 are provided with screw threaded brackets 26, andthe front part 22 of the cover is provided with apertures 28to receivescrews which engage the brackets 26, respectively, for securing thecover 20 to the frame 12. Said frame and its cover are preferably formedof sheet metal, and knockouts 30 may be provided in each of the endwalls 12 and 16, and, if desired, in the rear or side wall 18, forwiring the elements of the push button station tg the electrical deviceswhich are operable under the control of the switches of the station.

Pursuant to one of the objects of the present invention all of theopenings in cover 20 are of the same size.

More particularly, as here shown, the push button station v is providedwith a plurality of push button switches, in dicated at 32, 34, 36, 38and 40, with a rotary or selector 3 switch, the rotary knob of which isindicated at 42, and with a translucent pilot light cover indicated at44. The pilot light (not shown) may be mounted in any suitable way onwall 13. The openings in cover 20, which as stated, are of the same sizeare indicated by the numerals 32a, 34a, 36a, 38a, 40a, 42a, and 44a,respectively. With the exception of opening 42a, a ring is secured ineach of the cover openings, said rings being indicated at 32b, 34b, 36b,38b, 40b and 44b. Each ring has a snug fit in the companion coveropening and has its inner end bent over at the inner side of cover asindicated at 46 (see Figs. 2, 4 and 6), the peripheral shoulder 47 ofeach ring abutting the outer surface of the cover. As shown in Fig. 15,ring' 44b for the pilot light cover 44 is internally threaded forholding said pilot cover in position. Rings 32b, 34b, 36b, 38b and 40bconstitute guard and guide rings for the companion push buttons,respectively, and project forwardly of the front 22 of the stationcover. Ordinarily, with the exception of the stop button ring 32b, theserings are of such axial extent that the outer ends of said rings aresubstantially flush with the outer ends of the push buttons. However, inthe case of the stop button 32, the companion ring 32b is shorter thanthe other rings in order that the stop button may project beyond theouter end of the ring so that the stop button is more easily accessiblefor operation. It will be understood, that as usual, the push buttonsare movable axially of the companion openings through which they projectand, of course, axially of the companion rings which are secured in saidopenings.

As shown in Figs. 1 and 10, the rotary knob 42 of the selector switch isdisposed directly in the cover opening 42a and has a peripheral flange48 which overlaps the adjacent inner surface of the cover part 22 forpreventing removal of said knob through cover opening 42a. It will beobserved that the push buttons of the rotary knob 42a are each providedwith an appropriate legend or functional designation engraved on orotherwise applied thereto. As illustrated by Figs. 1 and 7, theselegends are horizontally disposed, for correct reading, both when thestation is mounted vertically, that is when the row of cover openingsextends vertically, as shown in Fig. 1, and also when said station ismounted horizontally, that is when the row of said openings extendshorizontally, as shown in Fig. 7. The manner in which this desirableresult is accomplished, pursuant to one of the objects of the presentinvention, will now be described. Although the push button 32 is shownas of the mushroom type, it will .be understood that said push buttonmay be of the same type as the other push buttons. Referring first tothe push button switches which are operable .by axial movement of theirpush buttons, respectively, each of said switches may be of theconstruction illustrated in Figs. 8, 9, l2 and 19. Each push buttonswitch comprises an insulation casing 50, which is provided with a pairof stationary contacts 52, 52a and another pair of stationary contacts54, 54a. A movable bridging contact 56 is movable longitudinally betweensaid pairs of contacts for engagement therewith or disengagementtherefrom, according to the requirements of the circuit controlled bythe particular switch. As shown in Fig. 8, bridging contact 56 isnormally in engagement with contacts 52, 52a. Said bridging contact isconnected by a shouldered screw pin 58 to the stem 60 of the pushbutton. A spring 62 normally holds contact 56 in engage ment withcontacts 52, 52a and also holds the companion push button in its forwardor projected position.

Although the push button may be turned about its axis, for the purposewhich will be presently described, contact member 56 is not turned butis held in alignment with the stationary contacts, by the adjacent innersurface portions of the switch casing 50 as will be readily apparentfrom an inspection of Fig. 12. In this connection it will be observedthat contact member 56 has a central opening 64 through which pin 58projects and that a spring 66 holds said contact member against the headof said pin, as clearly shown in Fig. 8. Referring to Fig. 9, it will benoted that the stem 60 is non-circular and projects through a similarlyshaped opening 68 of a retaining disk 70. This disk is provided with apair of ribs 72 and a pair of ribs 74 which are at right angles to eachother and which engage the casing 50 in grooves 76 and 78, the lastmentioned grooves being at right angles to grooves 76. Spring 62 whichholds the push button in its outwardly projected position bears at oneend thereof against the confronting surface of retaining member 70 andbears at its other end against the bottom of an inner circumferentialrecess provided in the push button as indicated at 80.

When it is desired to adjust the push button in order that its legendwhich is marked thereon may be horizontally positioned, as hereinbeforereferred to, for correct reading thereof, said push button is turnedabout its axis through During this turning movement the rounded ribs 72and 74 of the disk 70 move out of the grooves 76 and 78 in which theywere positioned, and at the end of the 90 turning movement of the pushbutton said ribs again enter said grooves, by reason of the pressure ofspring 62 on member 70, for releasably holding the push button in itsadjusted position. The stop but ton 32 which isof the mushroom type ashereinafter is more particularly described and is not integral with orotherwise immovably fixed to the axially movable stem, is adjusted inthe same way as the other push buttons as will be readily understood, itbeing noted in this connection that the stern 60a and the part 60bcorrespond to the stem 60 and the push button of the constructionillustrated in Fig. 8.

As hereinbefore indicated the knob or manually operable part 42 of therotary selector switch may also be positioned for correct reading ineither the vertical or horizontal mounting of the push button station.In this connection it will be noted that the knob 42 carries the legendsFor., Off and Rev. which of course mean forward, olf, and reverse,respectively. In order to enable the knob 42 to be correctly positionedsaid knob is provided with a non-circular, preferably square recess 82(Fig. 10), and the rotary stem 84 by which the selector switch isactuated is provided at its forward end with a non-circular projection86 which has a removable fit in said recess. Also, as herein shown aremovable set screw 88 may be provided for removably securing knob 42 tothe switch-actuating stem 84. It will be understood that the selectorswitch may be of any suitable construction and includes a plurality ofrelatively movable contacts (not shown) for making the desired switchconnections. However, it is preferred that the casing 90 of the selectorswitch be of the same size and external configuration as the casing ofthe several push button switches, as shown for example in Fig. 19. Thecross section of stem 84 is non-circular and has a sliding fit in acorrespondingly non-circular opening 92 in a releasable retaining member94 (Figs. 10, 11 and 17). Retaining member 94 is provided with a pair ofrounded projections 96 which are engageable in the recesses 98 andgrooves which correspond to the grooves 76, and 78 of casing 59.Referring to Fig. 9 it will be noted that casing 50 of the push buttonswitch is also provided with recesses 98, which, however, are not usedin the case of the push button switches since the ribs 72 and 74 of thepush button retaining members 70 are longer than recesses 98. On theother hand, the projections 96 of the retaining member 94 of theselector switch can enter recesses 98 as well as grooves 76 and 78. Inthis connection it will be understood that the provision of the.recesses 98 as well as the grooves in the push button switch casings 50and in the selector switch casings 9,0 enable the casings produced bythe same mold to be usedeither as casings of the push button switches orcasings of the selector switches. As in the caseof th pus but on s it h.a s ng. 100 holds the retaining member 94 in position butallows saidmember to be turned by stem 84. More particularly, as shown in Fig. 10,one end of spring 100 bears against member 94 and the other end of saidspring bears against the end wall of the recess 102 in the enlargedintegral cylindrical part 104 of stem 84. As shown by Figs. 10, 11 and22, said part 104 is provided with a plurality of circumferentiallyspaced longitudinal grooves 106, 108, 110, 112 and 114, in which alocking member of a key-lock hereinafter described is engaged forlocking knob 42 in a desired position. Grooves 6, 108 and 110 are usedfor the 3- position selector swtich indicated in Figs. 1 and 7, whilegrooves 112 and 114 are usedfor the 2-position selector switch the knobof which is indicated at 42' in Figs. 18 and 19. This feature of theinvention will be subsequently more specifically described.

As hereinbefore indicated, push button station may be provided with aStop button of the mushroom type. Since the head of such button islarger than the opening 32a of cover 20, it is necessary to attach thebutton to the push button stem 60a after the cover is placed inposition, and this in turn requires provision for removably attachingthe button to said stem. Also, it will be understood that it isnecessary to detach this button from the switchactuating stem in orderto effect the removal of cover 20 from frame 12. The constructionprovided for accomplishing these results is illustrated in Fig. 13. Ashere shown the shank 116 of the button is attached to metal cap 118 by ascrew 120 and a lock Washer 122. For this ripheral surface of cap 118 isflush with the outer cylindrical surface of head 60b forming a unitwhich has a movable fit, with proper clearance, in gulard ring 32b. Inthe attachment of the push button to the switch-actuating stem 60a, whenthe cover 20 is in position, the button 32 and cap 118 are firstattached to each other by screw 120 sufliciently tight to prevent freerelative movement of said button and cap but loose enough to allow thebutton to be turned. Then the cap 118 having the push button fastenedthereto is screwed onto the head 60b of the stem, and since the screwthreads of said cap and head are rather coarse, the edge of the capabutting the shoulder 132 at the base of the screw-threaded portion ofsaid head 60!) provides a definite stop against further turning movementof said cap in the same direction on said head. The push button 32 isthen turned until the Stop legend, engraved or otherwise appliedthereto, is in the proper horizontal reading position, according to Fig.l or Fig. 7, as may be required, after which the cap and button assemblyis unscrewed from the stern head 60b to permit tightening of thefastening screw 120 to tightly secure the button 3-2 to said cap in thecorrect reading adjustment thereon. Finally the cap 118 having thebutton 32 thus tightly fastened thereto is again screwed onto head 60b,completing the operation of attaching the button to the switch-actuatingstem for operation and with the Stop legend in the correct position. Itwill be understood that once the button'32 is thus secured to stem 60a,with the correct adjustment for the horizontal reading position of thelegend, the button may be turned in the same manner as the other pushbuttons in case it is desired to change the push button station from avertical mounting as shown in Fig. 1 to a horizontal mounting as shownin Fig. 7, or vice versa.

The push button station may be provided with a lockoff device asindicated above. This device is shown in Figs. 1, 7, 13 and 14 will nowbe described. Said lockoif device comprises the guard ring 32b which inthis case is provided with a slot 132 through whichthe part 134 of alock-ofi member 136 is movable with slight ,it is' desired to lock thepush button32 in its circuit opening position, said push button havingbeen moved inwardly, locking member 136 is moved so as to project itspart 134 through opening 132 from the position shown in Fig. 13 to theposition shown in Fig. 14, in overlying relation to the front surface ofcap 118, until the arcuate end 146 of said part 134 engages the shank116 of the push button. Anib or small projection 148 is provided on part134 of said locking member so that the latter is not movable by gravitywhen the push button station is in the horizontal position illustratedin Fig. 7. It will be understood however that a rather slight butpositive pull on the locking member 136 is suflicient to overcome theretaining effect of nib 148 when it is desired to retract the lockingmember from its locking or projected position shown in Fig. 14 to itsretracted or unlocked position shown in Fig. 13. With particular regardto Figs. 13 and 14, it will be apparent that member 136 coacts withmember 142 to form a frame of limited size when locking member 136 is inits projected position to overlie a portion of the push button as shownin Fig. 14. Such frame includes opposed horizontally and verticallyextending portions of members 136 and 142. This frame is of limited sizeand is suitable for insertion of a blocking member such as a padlockhasp for preventing unauthorized retraction of member 136 toward itspush button releasing condition illustrated in Fig. 13.

Referring to Figs. 18 to 20, there is shown a push button station of theflush type. Said station comprises a cover 150 and a frame 152 to whichsaid cover may be removably secured in the usual way as by screws 154.Said cover may be made of sheet metal, a in the case of cover 20 of pushbutton station 10 described above, but it may be desirable to provide acover which is cast, for example an aluminum or Zinccasting. When thecover is cast it is desirably thicker than the sheet metal cover and theholes in the cover for the switch and other elements are preferablyslightly larger than the push buttons which are of the same diameter asthose referred to above in the description'of push button station 10.Such larger holes cannot properly accommodate the pilot light cover 44or the selector switch knob 42' when, in accordance withone or more ofthe objects of the present invention, said last-mentioned elements areof the same size and construction as those used in a push button stationof a specifically different construction, such as that shown in Fig.- 1,for example. Accordingly, in order to enable these elements to be usedinterchangeably either with a sheet metal cover or with a cast metalcover additional elements are provided. In order to mount the pilotlight cover in position, an internally screw-threaded ring 156 isfastened to the station cover 150 in any suitable way as by screws 158.In the case of the selector switch, the knob 42' thereof which is of thesame size and construction as knob 42, hereinbefore described, ismounted in a flanged ring 160 which is fastened to the front of cover150 in any suitable way as by screws 162. It will be noted that theflange 48 of knob 42' is mounted between the front flange 164 of ring160 and the marginal surface of cover 150 around the cover opening 166.The thickness of the cover 150 results in the selector switch knob 42'being spaced from the end 86 of the switch-actuating stem whereby thelatter cannot be fitted into the recess 82 of 'said'knob in the mannerherein described with reference'to Fig. 10. "This difficulty is overcomeinaccordance with the present invention by the provision of a removableconnecting member 168 shown in Figs. 19 and 20. Said connecting member168 comprises a part 170 which fits into recess 82 in the knob, and apart 172 which fits on the end portion 36 of the selectorswitchactuating stem, as clearly seen in Fig. 20.

A mechanical interlock may be provided between any two adjacent pushbutton switches. An interlock de vice 174, made according to the presentinvention is illustrated in the push button station shown by Figs. 18and 19. It will be noted that the switch casings 50- are provided withgrooves 176 (Figs. 9, l9 and 21), and that the interlock device 174includes a fiat plate-like part 178 which has a slidable fit in the twoconfronting grooves 176 of two adjacent switches. A cross member 180 ispivoted intermediate the ends thereof on a shouldered pivot member 182which is secured to part 178. As illustrated in Fig. 19, the oppositeend portions of cross member 189 are in the paths of movement of buttons32 and 34 of the adjacent switches respectively. Cross member 180 allowseither push button to be depressed but prevents simultaneous depressionof both push buttons. In this connection, it will be understood that ifonly one push button is depressed cross member 180 can move on its pivot182 and therefore ofiers no impediment to the movement of one pushbutton at a time, while on the other hand if an attempt is made todepress both push buttons by an amount sufiicient to actuate theirswitches, the lower ends of both push buttons simultaneously engage theopposite ends of said cross member so that the latter cannot be movedout of the path of either of the two push buttons, thus preventingmovement of said push buttons to the extent required for the operationof the companion switches respectively. It will be noted that theinterlock device 174 may be readily placed in position between any twoswitches and may be easily removed when desired, since the interlockdevice is mounted and supported in the casing grooves 176 without anyauxiliary fastening device or fittings.

As hereinbefore indicated push button stations may be provided with akey lock. This is illustrated in Figs. 2 to 6, and as Will presentlyappear, the cover 20 of the enclosure of the push button station doesnot require any modification on account of the provision of the keylock.

As here shown, the key lock comprises a locking frame 184 which includesthe laterally spaced longitudinal bars 186 and 188, the end-connectingmember 190 and the cross members 192, 194, 196 and 198. The lockingframe is mounted for longitudinal movement adjacent the inner side ofthe front part 22 of the cover 20 by members 200 which as here shown arein the form of rings clamped against the inner side of the cover portion22 by the bent-over edge portions 46 of certain of the guard rings, asclearly shown in Figs. 2 and 4. Each of said frame mounting members 200is provided at diametrically opposite points with a pair of oppositelyoffset lugs 202, 204, at one side of member 200 and 206, 208 at itsopposite side. Said sets of lugs 202, 204 and 206, 208 form guides forthe side bars 186 and 188 of the locking frame and in the longitudinalmovement thereof and also hold the locking frame against movementtransversely of its own plane, as well as preventing lateral movement ofsaid locking frame. The cross members are each removably secured attheir opposite ends to the side bars 186 and 188 in any suitable way asby screws 210 which are received in companion threaded openings providedin said bars. It will be noted that said bars are provided with sets ofadditional openings, identified by the small circles on said barsdefining additional positions at which the various crosslocking-memhers, such as members 192, 194, 196, 198, may be disposed forlocking action. The locking members 192, 194, and 196 are each providedwith an arcuate recess 212, and locking member 198 is provided with asimilar arcuate recess 214 so that in the neutral position of thelocking frame, illustrated in Fig. 2, the locking members are clear ofthe push buttons or other elements to allow free movement thereof whenit is desired that they be unlocked, and also to permit the removal ofthe cover 20. In this connection it will be understood that when thelocking member 184 is moved longitudinally, one or more of the crosslocking members are disposed in the path of inward movement of the pushbuttons 40. Thus, it will be noted that when for example the lockingframe is moved toward the end Wall 16 locking members 194, 196 are movedto their locking positions under the inner ends of push buttons 38 and40 respectively and thereby prevent operation of said push buttons,while on the other hand if the locking frame is moved toward theopposite end of the cover 20 or end wall 14 of the frame 12, the lockingmember 192 is positioned under the inner end of the push button 36 andprevents operation of the latter. It will be readily understood thatprovision may be made for locking one or more of the push buttons whenthe frame 184 is moved in one direction to one locking position, andthat one or more of the push huttons may be locked when the lockingframe is moved in the opposite direction to its other position. It willbe observed that all of the cross locking members, including member 198,are reversible and may be positioned either like member 192 or likemember 194. For example, when it is desired to lock button 36 bymovement of the frame toward end wall 12 of the enclosure, cross member192 is removed from the position shown in Fig. 2, and placed in aposition in which it is secured in a pair of the above mentionedadditional openings indicated at 193, the arcuate portion 212 of saidcross member facing the end wall 16 of the enclosure. The cross lockingmember 198 is especially designed for locking the rotary selector switchin any of its three positions, when it is a 3-position switch asillustrated in Fig. l, or in either of its two position when it is aZ-position switch as illustrated in Fig. 18. For this purpose member 198is provided with a projection 216 in the arcuate recess 214, forreleasable engagement with the knob 42, or 42 as the case may be, saidlocking projection 216 being received in any one of the companionlocking recesses or grooves 106 to 114 hereinbefore described. In thisconnection it will be observed that the locking grooves 106, 108 and 110are provided for use in conjunction with locking projection 216 in thecase of the 3-position selector switch and that grooves 112 and 114 areprovided for use in conjunction with the locking projection 216 when theselector switch is of the 2-position type. In this connection it will beunderstood that the provision of a full set of the five locking grooveson the rotary stern of the selector switch enable the same casing to beused either for selector switches of the 3-position type or for selectorswitches of the 2-position type.

The locking frame 184 is movable to its neutral or to either of itslocking positions by a key-operated mechanism. Thus as here shown a keylock 218 is mounted on the front of the cover 20 near one end of thelatter, the casing 220 of said key lock being fastened in position bythe nut 222 (Figs. 3 and 5). A stationary guide 224 is fixed to theinner end of casing 220 for a lock bolt 226 and actuator which isslidable in said guide and which is operated by the turning movement ofthe key-operated lock barrel 228. The latter has an eccentric projectionor pin 230 which engages the member 226 in a groove slot 234 providedtherein. When the lock barrel 228 is turned by the proper key in onedirection, the locking frame is moved to a corresponding lockingposition and of course whenthe lock barrel is turned by the key in theopposite direction the locking frame is moved to its other lockingposition. It will be understood that in order to remove the key (notshown) from the. lock 218 it is necessary to turn the barrel 22.8 to oneof said two positions in which said frame has a locking action on one ormore of the push buttons and/or on the selector switch, as predeterminedby the positions of the cross locking members of the locking frame. Itwill be noted that the slidable locking member 226 which is operated bythe eccentric pin 230 of the lock barrel is secured to the crossconnecting member 190 of the locking frame. Also it will be noted thatsaid locking member 226 provides a lock for the cover 20 in one of thepositions of said locking frame, namely in the lower position of saidlocking frame viewing Fig. 1 or in the left hand position of saidlocking frame viewing Fig. 7. This is illustrated in Fig. 5 wherein thelocking member is shown in a locking position overlapping the inner endof bracket 26 which, therefore, prevents the removal of cover 20 sincethe lock casing 220 is fixed to said cover and is not removable exceptby access thereto at the inner side of the cover.

Thus, it is seen that the construction, organization and arrangement ofthe several parts of the push button station are well adapted to theaccomplishment of the several objects of the invention. It will beunderstood that a push button station may be provided with all of theauxiliary devices hereinbefore referred to or that all of such devicesmay not be required, or that only one or more of said devices may beprovided in any one push button station. It is to be noted however thatthe construction and arrangement and the relation between the cover 20of the enclosure. of the push button station and the various switchesand other elements and auxiliary devices are such as to enable thelatter to be used interchangeably for push button stations forsatisfying various specific requirements. It is believed to be obvious,however, that if a push button station requires only one or two switchesor other elements, enclosures of appropriate size, shorter than thatillustrated in Fig. 1 would ordinarily be provided. In actual practicethe enclosures may be stocked in a range of from one to eight sizes witha corresponding variation in the number of openings provided in thecovers respectively. However, the covers of different lengths do notvary in respect to the size of the openings therein, and accordinglyallow the use of switches and other elements of the same constructionand size in push button stations of different sizes. Also, ashereinbefore described, the switches and other elements can be appliedto push button stations which as described with reference to Figs. 18and 19 have cast metal covers. Finally it will be understood that theinvention is not to be limited to the specific push button stations anddevices herein disclosed, and that certain changes in the details ofconstruction and in the arrangement of parts may be made withoutdeparting from the underlying idea or principles of this inventionwithin the scope of the appended claims.

This application is a division of my application Ser. No. 371,526 filedJuly 31, 1953, now Patent No. 2,843,686, July 15, 1958, and of myapplication Ser. No. 42,718, filed August 5, 1948, now Patent 2,680,794,issued June 8, 1954, and certain features disclosed herein are claimedin said applications or in my application Ser. No. 117,596, which hasmatured into Patent 2,579,168.

Having thus described my invention, what I claim and desire to secure byLetters Patent, is:

1. In a push-button station, a push-button switch hav- 1 ing an axiallymovable stem for moving one switch contact in relation to another switchcontact, said stem having a manually operable part, a cover having anopening in which said part is axially movable, a ring in said openingsecured to said cover and surrounding said manually operable part, saidring having a slot, a member fixed to said cover and provided with aslot disposed laterally of said ring, and a locking member movablypositioned in said slots for releasable engagement with said manuallyoperable part for releasably holding the latter against axial movementin one direction, said locking member having an offset portion coactingwith said fixed member to define a padlock-receiving openingtherebetween when said locking member is in position to hold said keystem against axial movement as aforesaid.

2. A push button switch including an axially movable stem for moving oneswitch contact in relation to another, a cover through which said stemprojects, a manually operable part of said stem situated at one side ofsaid cover, a fixed member projecting from said one side of said coveradjacent to but spaced from said stem, said stem having a shoulder and alocking member having a portion movable toward and away from said stemso as to overlie and obstruct said shoulder when said stem is at oneposition in its axial motion, said locking member and said fixed memberhaving portions constituting a padlock-hasp encircling frame of limitedsize when said locking member is in its shoulder-obstructing position,said locking member being arranged to be obstructed against movement inthe shoulder-releasing direction when a padlock hasp is inserted in saidframe.

3. A switch having a movable stem for moving one switch contact inrelation to another, a cover through which said stem projects, amanually operable part of said stem situated at the front of said cover,a fixed member projecting from the front of said cover adjacent saidstem, a locking member operable into obstructing position relative tosaid movable stem in one position thereof and said locking member havinga first portion extending parallel to said cover but spaced forwardtherefrom, said first portion being guided by said fixed member forbackand-forth motion of the locking member relative to said stern, saidlocking member having a second portion extending from said first portiontoward said cover and parallel to said fixed member and spaced from saidfixed member, said locking member coacting with said fixed member todefine a padlock-receiving open frame of limited size when said stem isobstructed thereby whereby insertion of a padlock in saidpadlock-receiving opening will prevent operation of the locking memberout of its position preventing operation of the locking member out ofits position in which it prevents operation of said stem.

4. A switch having a movable stem for moving one switch contact inrelation to another, a cover through which said stem projects, amanually operable part of said stem situated at one side of said cover,a fixed member projecting from said one side of said cover adjacent saidstem, a movable locking member having a first portion extending parallelto said cover but spaced therefrom, said first portion being guided bysaid fixed member for motion of the locking member toward and away fromsaid stem, said locking member having a second portion extending fromsaid first portion toward said cover between said stem and said fixedmember and parallel to said fixed member and lying against said fixedmember at one part of its motion but being spaced therefrom duringanother part of its motion, and said locking member having a thirdportion extending from said second portion and cooperable with said stemto prevent operation thereof when said second portion is spaced fromsaid fixed member, said fixed member and said first and second portionsof said locking member jointly defining a padlockreceiving opening whensaid second portion is spaced from said fixed member, whereby insertionof a padlock in said padlock-receiving opening will prevent operation ofthe locking member out of the position in which it prevents operation ofsaid stem.

5. A locking arrangement for a switch, including a cover plate, a switchactuator having a manually engageable portion at the front of the cover,and locking means for the switch actuator including a movable lockingmember cooperable with the switch actuator as an obstruction preventingoperation thereof and removable from such cooperation, said lockingmeans including two elements 2,979,581 E3. 7 l2 projectingperpendicularly from the front of the cover from removal fromactuator-obstructing position when the and a third element spaced fromthe front of the cover hasp of a p l c is inserted in Said p gbutextending parallel thereto, said locking member including at least oneof said elements and being movable References Cited In theme of thlspatent in relation to at least one other of said elements to define 5UNITED STATES PATENTS a padlock-hasp encircling opening when saidlocking mem- 2,123,058 Maslin et a1. July 5, 1938 ber is in position toobstruct said switch actuator, and 2,370,877 Robbins Mar. 6, 1945 saidlocking member being arranged to be obstructed 2,523,943 Choppa Sept.26, 1950

